<!DOCTYPE html>
<html lang="en">
	<head>
		<meta charset="UTF-8" />
		<meta http-equiv="X-UA-Compatible" content="IE=edge" />
		<meta name="viewport" content="width=device-width, initial-scale=1.0" />
		<title>Document</title>
	</head>
	<style>
		.outer {
			width: 500px;
			height: 500px;
			background-color: pink;
		}
		.mid {
			width: 300px;
			height: 300px;
			background-color: cyan;
		}
		.inner {
			background-color: red;
		}

		.fade-enter-active,
		.fade-leave-active {
			transition: opacity 0.3s ease-in-out;
		}

		.fade-enter-from,
		.fade-leave-to {
			opacity: 0;
		}

		.fade-enter-to,
		.fade-leave-from {
			opacity: 1;
		} 
	</style>
	<body>
		<div>
			<p>
				<span>hello&nbsp;&nbsp;</span>
				<input/>
			</p>
		</div>
		<button onclick="change()">change</button>
	</body>
	<script>
		document.querySelector('div').setAttribute('file','')
	</script>
</html>
